Caller ID standards using analog facilities are used in a variety of countries, including the United States. Examples of analog Caller ID standards include, but are not limited to the following: IDA TS PSTN 1-A, GR-127-CORE, Telecordia GR-30, TIA/EIA-777, and GR-30-CORE. As analog Caller ID standards evolved, so did the rules which defined the capabilities of Caller ID. In the United States, the Federal Communications Commission (FCC) regulates the information that can be sent using analog Caller ID. Currently, this information is limited to information pertaining to the initial establishment of a call. A reason for this FCC regulation is that toll charges on the Public Switched Telephone Network (PSTN) are not incurred until the called party answers the incoming call. The regulation therefore imposes limits on the information that can be passed to the called party for free.
Analog Caller ID standards that are defined for the PSTN send information associated with the initial establishment of a communication such as the caller's telephone number, the time of the call, the date of the call, the caller's name, and call waiting information. The analog Caller ID standards also include parameters for message waiting. Like the other analog Caller ID messages/parameters, message waiting information relates to a prior attempt to establish the communication (i.e. a message was left after the attempted call was made). Other information such as test information to determine if the initial establishment of a call can be accomplished can also be sent under current analog Caller ID standards.
As a result, information not pertaining to attempts to initially establish a communication is not sent using analog Caller ID standards. This limits the capability of systems that rely on PSTN and analog Caller ID to only use the information that is currently available using analog Caller ID. For example, U.S. Pat. No. 6,324,263 discloses a system that routes a communication based on the telephone number of the caller by looking up the caller's telephone number in a routing table. If there is a match, then the call is routed to the extension or telephone number in the routing table.
The use of a database look-up, to match the Caller ID to other important information, is well known in the prior art. For example, it is common practice for 9-1-1 Public Safety Access Points (PSAPs) to map the Caller ID information to vital information that is maintained in the PSAP database, notably the street address associated with the telephone number, directions to that location, and the local availability of resources, such as fire hydrants. This PSAP application illustrates an important problem with the current Caller ID implementation: The mapping of Caller ID to a specific location is reliable only for PSTN land lines. It does not work for mobile devices, such as cellular telephones and Voice over Internet Protocol (VOIP) telephones (e.g. a VOIP soft phone on a mobile personal computer) that can register to the PSTN with the same phone number from different locations. There is a need for an analog Caller ID protocol that solves this problem, while staying within the scope and objectives of the FCC rules.